THE SEMIMETRIC 6x6 RESEAU CAMERA FOR THE CLCSE RANGE PROJECTS
OF HIGH ACCURACY
Jôzef Jachimski and Adam Boron
The University of Mining and Metallurgy (AGH)
Cracow, Poland
ABSTRACT:
The way of adaptation of photo-camera Pentacon Six TL for recording of reseau pictures is presented. An
economic and accurate way of reduction of photocoordinates to the reseau pattern as well as results of
camera calibration are described. This non-expensive camera is meant as a toc! for industrial and architectural
close-range applications.
KEY WORDS: Instrument Design, Camera-reseau, Close range, Non-metric, Accuracy.
1. INTRODUCTION
Semimetric cameras, being accurate, inexpensive and
easy to use, are each year more often used in various
engineering and scientific applications and in record-
ing of historic monuments. At the Photogrammetric
Research of The University of Mining & Metallurgy
(AGH) in Cracow a semimetric camera was con-
structed. It was built on the basis of the Pentacon
Six TL photographic camera, by equipping it with
the 1.6 mm thick glass plate with reseau crosses.
Furthermore a circular level was attached to the
camera body and a mark was introduced to the
field of view of the camera view finder to enable
more accurate angular camera orientation in the
field. There also was corrected the position of the
zero-mark of the distance scale on the camera ob-
jective due to the change of optical properties after
a glass plate was inserted to the optical system.
Some changes were done to the film flattering device
to make there more room for glass-plate which was
added up.
The camera to which the reseau plate had been inserted
not only better flattens the film in the fiducial reseau
plane, but also registers on each picture the shadows
of 49 (7x7) crosses (fig2) which correspond to the
reseau master pattern in the camera. No doubt, the
most accurate reduction of the photograph errors would
result from the transformation of each measured point
onto the nearest four reseau crosses. From the point
of view of the economy of time, however, it would be
better to reduce the number of reseau active crosses
which are to be measured on each semimetric
photograph. It was proofed that 9 reseau active crosses
give the most convenient configuration. The pictures
made using semimetric-reseau camera fit well for high
precision surveys, can be evaluated using analytical
plotting techniques and also the old analogue-type
plotters (Boron & Jachimski, 1991).
Fig.1 The Pentacon Six TL photographic camera
2. THE ADAPTATION OF CAMERA
2.1. Introductory assumptions
In the professional periodicals there are several
reports about good surveying results achieved using
6X6 cm amateur carzeras, or even using 24x36 mm
cameras.
In our case, as the result of the survey of available
cameras, three of them were selected as more or
less suitable for adaptation for precise photogram-
metric works. This were 6X6 cameras: Pentacon Six
